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Damage to Papaya Caused by
Thrips parvispinus (Karny)
In 2006, Thrips parvispinus was first detected in Puna, Hawai‘i (E. Villalobos, M. Wright, and S. Swift,
public presentation, September 2007). In 2010, heavy infestations were also observed on O‘ahu,
causing severe economic damage to papaya fruits and foliage. The following are symptoms
observed on papaya flowers, fruits, and foliage from a field severely populated with T. parvispinus.
It is suspected that T. parvispinus is responsible for the type of damage shown below.
Damage to young papaya fruit
from thrips feeding on and in
flower buds. Note the scarring.
Severe fruit scarring, as a result of
heavy thrips infestation and feeding
in papaya flowers.
Deformation and scarring of
flower bud.
Tell-tale sign of thrips damage: Leaves have a tattered appearance and are
deformed and distorted. The leaf blade may have holes and yellowed areas
and gaps in the leaf margin.
Close up of adult Thrips parvispinus (Karny) on papaya. Thrips are very tiny
insects that are difficult to find and see.
If left untreated, the entire top of
the plant may become affected. It
is suspected that gaps in the fruit
column may result when flowers
are severely damaged by thrips
feeding. However, the thripsinduced abortion of papaya flowers needs to be studied further.
Monitor your fields by looking at
new growth for the tell-tale signs
of thrips damage.
Recommendations
•Familiarize yourself with the signs of thrips damage: One clear
sign of thrips damage is malformed young leaves.
•Scout fields on regular basis and inspect the young growth for
early detection.
•The thrips live and feed in papaya flower buds and the growing shoot (Villalobos, personal communication).
•Thrips feed by piercing and sucking on plant tissue in the
flower buds and on very young papaya leaves.
•Targeting your spray at the flowers and growing shoot of the
papaya plant, where the thrips live and feed, will help to provide maximum thrips suppression.
• Rotate approved insecticides from different IRAC mode-ofaction classes to minimize pest resistance.
Prolonged heavy infestations
of thrips may result in damage
to the entire fruit column. The
russeting and meandering scars
may be easily confused with mite
damage or spray phytotoxicity.
Poster produced by Jari Sugano, Randall Hamasaki, Ethel Villalobos, Ming Yi Chou, Mark Wright, Steven Fukuda, Sabina
Swift, Stephen Ferreira, Dick Tsuda, Maria Derval C. Diaz-Lyke and Stuart T. Nakamoto of the University of Hawai‘i at Mānoa,
College of Tropical Agriculture and Human Resources, in collaboration with the Hawaii Papaya Industry. Funding support from
USDA Risk Management Agency grant # RMA J6303657. Special thanks to members of the Hawaii Papaya Industry Association (HPIA) for providing LIFE access to their fields and farmers; thanks to CTAHR OCS for publication editing and design.
The area of scarred tissue enlarges as
the fruit develops. This type of damage could be easily confused with
that caused by the red and black flat
mite.
Suspected thrips damage on the
blossom end of fruits.
Target your spray at the flowers
and growing shoot of the papaya
plant. This is where T. parvispinus
lives and feeds. Use an approved
insecticide that is effective on
thrips. Young papaya leaves and
fruit tend to have waxy surfaces
and can be hard to wet. A surfactant such as Latron B-1956 should
be used to improve the spreading and wetting of the leaves
and thus provide better control.